1. Field of the Invention
This invention relates in one aspect to a method for determining vision defects and for collecting data for correcting vision defects of the eye by interaction of a patient with an examiner and apparatus therefor.
2. Background Information
The primary or traditional method for correcting vision defects, such as, correcting myopia, hyperopia, and astigmatism, comprises selection of and mounting of particular lenses in a spectacle-frame by the physician for a vision test, and the patient establishes his optimal faculty of vision based on the gradation of the test lines of a test image. In accordance with this traditional methods the patient can obtain optimally suited glasses for correction of significant, or approximate or gross, vision defects, but the method substantially may provide only for approximate or rough correction of vision defects.
This classical approach or method has now been replaced by objective metrological methods which are performed without active participation by the patient. Examples include automatic refractometers.
Next to the objective determination of significant vision defects, various topographical apparatus and devices for measuring eye aberrations, such as, aberroscopes or aberrometers, are utilized so as to determine patient-specific cornea topographies and, as well, substantially all wavefront aberrations. On the basis of such metrological data, the patients are treated, for example, by using an excimer laser system, to have specific topographies applied or formed on the cornea of the eye, which topographies are to ensure an optimal faculty of vision (compare: P. Mierdel, H.-E. Krinke, W. Wiegahnd, M. Kaemmerer, T. Seiler, xe2x80x9cMe xcex2platz zur Bestimmung der monochromatischen Aberration des menschlichen Auges {Test station for the determination of the monochromatic aberration of the human eye}xe2x80x9d, OPHTHALMOLOGE, 1997, 94; pages 441-445, SPRINGER VERLAG, 1997).
In these determinations, or measurements or metrological approaches, a double-pass through the optics system of the eye needs to be realized due to technical reasons. The main problem with this method resides therein that the uneven or odd-valent aberrations are determined in a falsified manner. A reduction of the problem with the double-pass method can be obtained, for example, by use of different numerical apertures for the entering and exiting light. Another approach comprises inducing of a fluorescence on the cornea so as to preclude these metrological errors (compare: LASER FOCUS WORLD, April 1999, pages 35-36).
In the methods available in the state of the art, an optical apparatus or system, the eye, which is a rather dynamic system, is precisely measured and corrected, but only in a momentary or snapshot-like manner. This suggests errors, particularly in the desired correction of higher-order aberrations which preclude attainment of an optimal faculty of vision. This is indicated thereby that with the measurements of eye aberrations of eyes actually having the best faculty of vision, occasionally high aberrations are shown, and till this day it is not known with certainty whether a physical correction of the eye actually increases or even worsens the faculty of vision of the eye.
It is further known that aberrations of the human eye can be compensated with the aid of adaptive optics, so as to realize high-resolution images of the cornea for medical investigations (compare: LASER FOCUS WORLD, August 1998, pages 18-22).
A microscope with an adaptive optics is described in German patent publication No. 19 733 193 A1. This publication mentions various wave modulators.
In the paper xe2x80x9cSupernormal vision and high-resolution retinal imaging through adaptive optics,xe2x80x9d by Liang et al., J. Opt. Soc. Am. A, Vol 14 (1997), pages 2884-2892, apparatus and method are described with which by way of a wavefront measurement, using a deformable mirror, the feasibility of an adaptive correction of eye aberrations as well as photographic images of the retina is achieved.
U.S. Pat. No. 5,777,719 issued to inventors Williams et al. on Jul. 7, 1998 and entitled xe2x80x9cMethod and apparatus for improving vision and the resolution of retinal images,xe2x80x9d also describes a method and a device for obtaining improved photographic pictures of the retina, with the apparatus, using a deformable mirror, being capable of obtaining corrected pictures of the retina using a CCD-camera.
It is an object of the invention to provide a method for determining vision defects and for collecting data for correcting vision defects of the eye by interaction of a patient with an examiner and apparatus therefor.
It is also an object of the invention in one aspect to make available a method, and apparatus, which serve in the acquisition of correction data for the correction of eye aberrations, with the translation of such data leading to an improved faculty of vision of the patient.
One feature of the invention to accomplish the foregoing objects resides in a method for determining vision defects and for collecting data for correcting vision defects of the eye by interaction of a patient with an examiner, said method comprising: projecting an image into the eye of the patient with an adaptive optical system; said adaptive optical system comprising at least one adaptive optical element; said at least one adaptive optical element being configured to have its optical characteristics changed by an electrical signal, in an attempt to minimize distortions of the image as perceived in the eye and the brain of the patient; determining the presence of distortions of the image as perceived in the eye and the brain of the patient by interaction of the patient with the examiner; providing an electronic control system; said electronic control system being configured to control the optical characteristics of said at least one adaptive optical element through outputting of an electrical signal; modifying the optical characteristics of said at least one adaptive optical element through outputting of an electrical signal of said electronic control system and obtaining a modified image of the image in the eye of the patient, in an attempt to correct for the distortions of the image as perceived in the eye and the brain of the patient; evaluating said modified image by interaction of the patient with the examiner; repeating said modifying step and said evaluating step and obtaining a modified image having minimized distortions as perceived in the eye and the brain of the patient; determining the optical characteristics of said at least one adaptive optical element, as modified, resulting from said modified image having minimized distortions as perceived in the eye and the brain of the patient; and computing vision correcting data for the eye being examined, from said optical characteristics of said at least one adaptive optical element, as modified, resulting from said modified image having minimized distortions as perceived in the eye and the brain of the patient.
Another feature of the invention to accomplish the foregoing objects resides in a method for determining vision defects and for collecting data for correcting vision defects of the eye by interaction with a patient, said method comprising: forming an image in the eye of the patient with an optical system; said optical system being configured to have its optical characteristics changed by at least one signal, in an attempt to minimize distortions of the image as perceived in the eye and the brain of the patient; determining the presence of distortions of the image as perceived in the eye and the brain of the patient by interaction with the patient; providing an electronic control system being configured to control the optical characteristics of said optical system through outputting of at least one signal; modifying, at least once, the optical characteristics of said optical system through outputting of at least one signal of said electronic control system and obtaining a modified image of the image in the eye of the patient, in an attempt to correct for the distortions of the image as perceived in the eye and the brain of the patient by interaction with the patient; determining the optical characteristics of said optical system, as modified, resulting from said modified image of the image in the eye of the patient having minimized distortions as perceived in the eye and the brain of the patient; and computing vision correcting data for the eye being examined, from at least one signal indicating said modified optical characteristics of said optical system.
A further feature of the invention resides in an apparatus for determining vision defects and for collecting data for correcting vision defects of the eye by interaction between a patient and an examiner, said apparatus comprising: an adaptive optical system configured to form an image in the eye of the patient; said adaptive optical system being configured to have its optical characteristics changed by at least one signal, in an attempt to minimize distortions of the image as perceived in the eye and the brain of the patient; an electronic control system operatively connected to said adaptive optical system; said electronic control system comprising an arrangement configured to modify, at least once, the optical characteristics of said adaptive optical system, and being configured to output at least one signal to obtain a modified image, in an attempt to correct for the distortions of the image as perceived in the eye and the brain of the patient through interaction with the patient; an arrangement configured to determine the optical characteristics of said adaptive optical system, as modified, resulting from said modified image formed in the eye of the patient having minimized distortions as perceived in the eye and the brain of the patient; and an apparatus configured to compute vision correcting data for the eye being examined, from at least one signal indicating said modified optical characteristics of said adaptive optical system.
Thus, the foregoing objects are accomplished in one aspect of the invention by the apparatus, and in one aspect of the invention by the method, in accordance with the independent claims. Further preferred embodiments are indicated in the dependent claims.
More particularly, the object in accordance with one aspect of the invention is accomplished by an apparatus for the determination of correction data for the correction of eye aberrations of a patient, said apparatus comprising an optics system, and the apparatus further comprising an adaptive optics, and/or a wavefront modulator, as well as an arrangement for the display of test images, to be displayed by way of the adaptive optics, and a control system. This apparatus makes it possible for test images to be shown to the patients, by means of the adaptive optics, which test images can be evaluated in subjective manner by a patient. By way of the subjective assessment of the test images that are displayed on the adaptive optics, minute aberrations of the eye can be recognized and the correction that has been determined by the patient as subjectively most suitable compensation of eye aberrations can be determined. The alignment or position of the adaptive optics at the moment in which the corrections are perceived as subjectively optimum conditions, accordingly, corresponds to the correction data for the correction of eye aberrations.
The optical system serves to align and/or focus the direction of rays from the eye to the adaptive optics. Such an optical system may be provided, for example, by an arrangement of lenses.
It is preferred that the adaptive optics is a modulator, particularly, a wavefront modulator. Such adaptive optics can be realized in various embodiments. Thus, there are available transmitting modulators based on LCD-basis, or reflecting modulators having moveable membranes. These modulators with moveable membranes can be classified on the basis of their control, for example, piezoelectric, electrostatic, and bimorph membranes. Electrostatic membrane mirrors are particularly preferred to configure the adaptive optics, or electrically controlled micro-mirror arrays. Reflecting and also transmitting media may be employed to configure the adaptive optics.
The arrangement for the display of test images by means of the adaptive optics may comprise, in the case of reflecting elements of the adaptive optics, a projector, which projects the test images onto the reflecting elements of the adaptive optics, which test images then reach the eye, preferably, by way of the optical system. In the case of an adaptive optics with transmitting media, a projector is contemplated which projects through the adaptive optics onto the eye. It is furthermore possible, in the case of an adaptive optics with LED-display, for the arrangement for the display of test images to utilize electrical signals which generate corresponding test images and/or portions of such test images on the individual LED-surfaces.
It is preferred that the test images are configured in such a way that they react, in reference to the aberrations that are to be investigated, particularly pronounced to the modulated wavefront through the adaptive optics. Thus, in the test image a portion of an image error can be traversed in scanning mode and the wavefront can be deformed in such a way that only one individual image error is changed or compensated. By way of the test image that has been determined by the patient, by way of iterative analysis, to be subjectively the most distortion-free test image, a subjectively aberrations-free image is produced on the eye.
The control system is preferably a computer. The adaptive optics can be controlled by way of the control system, and with it one can determine the correction data for the correction of eye aberrations. This control system preferably comprises a computer which controls n x m micro-optics elements, whereby each element can be individually controlled in terms of angle of inclination and in terms of adjustment of height. This, means that the wavefront can be changed in a localized defined manner.
The correction data are preferably utilized to determine an optimal, patient-specific, refractive element. Refractive elements preferably comprise IOLs (intra ocular inserts), ICLs (implantable contact lenses), contact lenses, and spectacle glasses. It is particularly preferred that the correction data are utilized to determine the beam alignment for a contemplated laser treatment of the eye, particularly of the cornea.
It is preferred that the adaptive optics is comprised of a plurality of mirrors that can be individually adjusted. These individual mirrors can be repositioned in conformity with the subjective judgement of the patient in such a way that the mapped test image is subjectively and optimally viewed by the patient. Thus, by means of the adaptive optics, the selected test images, and the corresponding evaluation algorithms, the actively physiologically evaluated mirror positions can be converted into correction data for a correction of eye aberrations, so as to provide an optimal faculty of vision for a patient. The mirror positions in their entirety define a data set which describes that correction that has been sensed to be the optimal correction, based on the adaptive optics: the adaptive data.
It is particularly preferred that the adaptive optics is configured substantially as a segment of a sphere. This makes it possible to determine the correction data from the normals of the positioned mirrors, because the adaptive optics in the configuration of a segment of a sphere corresponds directly to the outer shape of the eye. This obviates otherwise required conversion of the sensed parameters into the correction data.
In a particularly preferred embodiment according to one aspect of the present invention, a control system is contemplated, which serves to align or adjust the position or attitude of the adaptive optics. In this manner, through changes of the individual mirrors any aberration behavior or condition of an eye can be compensated and the test images for specially preselected aberrations in the human eye thus displayed can be processed. By means of this control system it is also possible to display predetermined sets of aberrations of higher-orders and these can be evaluated in a dialogue with the patient. It is particularly preferable that by means of the control system, the adaptive optics, in the scanning mode, tests a series of eye aberrations, to thereby determine the optimal setting of the adaptive optics for an optimal faculty of vision of the patient.
In a preferred embodiment of one aspect of the present invention, the embodiment comprises an aberrations measuring arrangement, particularly an aberrations measuring device, such as, an aberroscope or aberrometer, for the determination of aberration data which correspond to the objective aberrations of the eye. Such aberrations measuring arrangements, for example, refractometers, or aberroscopes, and/or wavefront analyzing or measuring apparatus, can determine the objective eye aberrations and, for verification of the computed correction values of the patient, they can be confirmed or corrected by the patient by way of an adaptive optics.
Thus, in accordance with one aspect of the invention, subjective correction values, obtained by means of an adaptive optics, and objective correction values, obtained by means of an aberroscope, can be advantageously combined.
It is particularly preferred that the correction data for the correction of eye aberrations are determined by means of a second control system. It is preferred that this second control system comprises a computer. By means of applicable software, the set of correction data can be established, on the basis of adaptive data or, respectively, aberration data. It is preferred that the aberration data are determined as rough or approximate values, so at to determine the adaptive data, by way of a subjective assessment of the test images, by means of the adaptive optics, and to utilize such adaptive data as basis for the correction data. It is also within the scope of the invention that use is made of the average or mean value of the adaptive data and of the average or mean value of the aberration data as the basis for the correction data.
The object of one aspect of the present invention is also particularly accomplished by a method for the determination of correction data for the correction of eye aberrations, in which method in a first step are determined, by means of an adaptive optics, adaptive data relating to a subjectively optimal correction adjustment of the eye, and in a further step are determined the correction data for the eye corrections which correction data are based on the adaptive data. It is an advantage of this method that the correction data are obtained in an a priori active, physiologically assessed metrological method, such correction data serving to correct vision defects of the eye, such vision defects negatively impacting the faculty of vision. This means that no longer does use need to be made of an error-prone determination of objective display errors in a dynamic-organic display apparatus in which determination no use is made of the characteristics, or features, of the signal processing by the human nervous system, respectively the brain. In a dialogue with the patient, in accordance with one aspect of the invention, by means of the adaptive optics, those values are determined which correspond to the optimal correction condition; this may be different from the condition which was found to be the optimal condition in an objective assessment.
In a preferred embodiment of one aspect of the present invention, additional aberration data are gathered which correspond to the objective aberrations of the eye and the correction data are determined on the basis of the adaptive data and the aberration data. By way of a comparison of the subjectively determined data and the objectively determined data, it is possible to point to the importance of the physiological influences of the image processing.
It is particularly preferred that with the aid of objective metrological methods, using the aberrations measuring arrangements or, respectively, the mentioned measuring devices, the coarse or significant correction values are determined and they are utilized as a starting point for the further determination of the final correction data by way of the subjective method, that is, a method comprising an active physiological assessment.
In a preferred method of one aspect of the present invention the adaptive data for a subjectively optimal correction condition of the eye are obtained by a subjective assessment of modified test images by the patient, modified by the change of mirror positions of mirrors of the adaptive optics. The change of the mirror position of the individual small mirrors allows one to compensate for any aberration condition of the eye. The position of the individual small mirrors, or micromirrors, is then establishing that condition which affords the maximum of compensation for the eye aberrations of the patient. The position parameters of the individual small mirrors, accordingly, correspond to the subjectively optimal correction of the eye aberrations. These position parameters of the mirrors can easily be captured and provide a good utilization basis for the determination of the adaptive data and/or the correction data.
The above-discussed embodiments of the present invention will be described further hereinbelow. When the word xe2x80x9cinventionxe2x80x9d is used in this specification, the word xe2x80x9cinventionxe2x80x9d includes xe2x80x9cinventionsxe2x80x9d, that is the plural of xe2x80x9cinventionxe2x80x9d. By stating xe2x80x9cinventionxe2x80x9d, the Applicants do not in any way admit that the present application does not include more than one patentably and non-obviously distinct invention, and maintains that this application may include more than one patentably and non-obviously distinct invention. The Applicants hereby assert that the disclosure of this application may include more than one invention, and, in the event that there is more than one invention, that these inventions may be patentable and non-obvious one with respect to the other.